Pressure balanced rotation spool valve

ABSTRACT

The present invention regards a valve arrangement comprising a housing ( 1 ) and an mainly cylindrical valve element ( 2 ) arranged rotatable within the housing, where the housing has at least one supply port ( 11 ) and at least one exhaust port ( 12 ) and at least one outlet/inlet opening ( 13,14,15,16 ). These ports and opening are arranged in a distance from each other along a rotation axis for the valve element. The valve element comprises at least one first bore extending along the rotation axis connecting the supply port with the at least one outlet/inlet opening in one position of the valve element, and at least one second bore extending along the rotation axis connecting the same outlet/inlet opening with the exhaust port in a second position of the valve element, the bores being configured such that they are separated from each other.

The present invention regards a valve arrangement.

There are sometimes needs to coordinate several fluid flows, which maybe done by operating several valves at the same time with a commoncontrol system. However, there may also be a need to be sure that theoperation is synchronized. One such solution is described in U.S. Pat.No. 3,969,046, describing a metering pump system, where there inrelation to the system is described a valve arrangement with valvehousing and a valve element arranged rotating within the valve housing.The valve element is formed with indentations in its surface such thatduring the rotation of the valve element, it connects an inlet with acommon outlet/inlet opening and closing an outlet and in anotherposition connects the outlet with the common outlet/inlet opening andclose the inlet.

The present invention gives an alternative solution to this problem witha valve arrangement as defined in the attached claims.

There is provided a valve arrangement comprising a housing and a mainlycylindrical valve element arranged rotatable within the housing. Thevalve housing has at least one supply port, at least one exhaust portand at least one outlet/inlet opening arranged in a distance from eachother along a rotation axis for the valve element.

There is at least one supply port, forming a supply port set, where theset is formed by one, two or more supply ports. If there are more thanone supply ports in the set, these are arranged around one circumferenceof the valve element. The supply ports are then arranged lined up aftereach other around one circumference of the valve element, where thecircumference is arranged coaxial with a rotation axis of the valveelement. A fluid will normally flow through the supply ports and intothe valve element. In a similar manner are there arranged at least oneexhaust port, forming a set of exhaust ports, there being one, two,three or more exhaust ports arranged around a circumference of the valveelement. A fluid will normally flow from the valve element and outthrough the exhaust port. The at least one outlet/inlet opening may bemore than one outlet/inlet opening forming a set of outlets/inlets,where a set is defined in a similar manner as in relation to the supplyport and exhaust port. There may also be arranged one, two, three, fouror more sets of outlet/inlet openings, where these sets are arranged ina distance from each other along the rotation axis of the valve element.These sets may then only comprise one outlet/inlet opening each, butpossibly two openings each or four openings each. There may in each setbe an equal amount of inlet/outlet openings, or there may be differentamounts of inlet/outlet openings in different sets. Each set ofinlet/outlet openings are arranged around one circumference of the valveelement. If there is more than one opening in a set of inlet/outletopening, the openings will normally be spaced with mainly equal distancearound the circumference of the valve element. The openings in one setof inlet/outlet openings will normally be arranged at different anglesaround the valve housing compared with the inlet/outlet openings in aneighboring set of inlet/outlet openings. Openings of different set arethereby staggered around in the valve housing.

Further the valve element comprises according to the invention at leastone bore extending along the rotation axis connecting the supply portwith the at least one outlet/inlet opening in one position of the valveelement, and at least one second bore extending along the rotation axisconnecting the at least one outlet/inlet bore with the exhaust port inanother position of the valve element, the bores being configured suchthat they are separated from each other. A bore in the valve elementwill never connect the supply port with the exhaust port.

According to an aspect of the invention there may be at least twooutlet/inlet opening sets in the valve housing and these twooutlet/inlet opening sets are arranged at a distance from each otherseen along a rotation axis of the valve element. These outlet/inletopening sets would lead to/from different units outside the valvearrangement. The outlet/inlet opening sets, when there are at least twoof them, and the bores, are being configured such that the first bore inone position of the valve element is in contact with one of theoutlet/inlet opening sets and in another position of the valve elementis in contact with a second outlet/inlet opening set. The outlet/inletopening sets and the first and second bore are such configured that theyin one position of the valve element is in contact with one outlet/inletopening set, and in another position is in contact with anotheroutlet/inlet opening set axially displaced in the housing compared withthe one outlet/inlet opening set.

According to another aspect the at least one outlet/inlet opening setmay be arranged between the supply port and the exhaust port seen alonga rotation axis for the valve element.

According to another aspect the bores may be formed as grooves in anouter surface of the valve element. Another embodiment is to have thebores formed within the valve element.

According to another aspect the valve element may comprise acircumferential groove connecting the supply port with the first bore,and a second circumferential groove connecting the exhaust port with thesecond bore. In another embodiment this circumferential groove may beformed in an inner surface of the valve housing. With such a grooveeither in the valve element or the valve housing there may be only onesupply port and one exhaust port. With only one supply port and thegroove in the outer surface of the valve element or in the inner surfaceof the valve housing, there will always be a feed of fluid to the firstbore in the valve element.

According to another aspect there may be two first bores arranged onopposite sides of the valve element and two second bores arranged onopposite sides of the valve element. The bores are then being arrangedwith equal distance from each other. The bores are arranged such thatthe two first bores are arranged at 0 and 180 degrees and the two secondbores are arranged at 90 and 270 when seen in a cross section. A firstbore has a second bore as neighboring bore on both sides seen in adirection around the circumference and a second bore has a first bore asneighboring bore on both sides. Around the circumference there arealternating first and second bores. Such a solution will give a pressurebalanced rotating valve arrangement. Equal grooves on opposite sides forfluid either coming from the supply port or leaving through the exhaustport will induce equal pressure forces acting on the valve element in aradial direction.

According to another aspect there may be arranged outlet/inlet openingsets connectable to two different units in the valve housing, where theoutlet/inlet opening set connectable to a first unit is staggered aroundthe housing in relation to the outlet/inlet opening set connectable to asecond unit, thereby leading fluid towards/away from one unit in a firstposition of the valve element and then in a second position of the valveelement leading fluid towards/away from a second unit. Outlet/inletopening sets leading to/from different external units will be positionedat different axial positions in the valve housing. If there are twofirst grooves there will preferably also be two outlet/inlet openingsleading to the same external unit, but positioned at the same axialposition in the housing.

According to another aspect the housing may have one set with two supplyports and one set with two exhaust ports and at least one set with twooutlet/inlet opening, where the openings of each of these sets arrangedat opposite sides around a circumference of the valve housing inrelation to each other. Another possibility is to have sets with threeopenings and also have three first and second grooves in the valveelement, where these three openings are being arranged with equaldistances around a circumference. Yet another possibility is to havesets with four openings, and four or possibly two first and secondgrooves within the valve element, where these four openings may bearranged with equal distances around the circumference.

According to another aspect there may between the valve element and thevalve housing be arranged a ceramic liner. The ceramic liner may then beformed with the same number of openings and or grooves as there is inthe housing.

According to the invention there is also provided a system forpressurizing a fluid with the use of a motive fluid. The fluid to bepressurized may be liquid and the motive fluid may be a gas. There is inthe system provided a valve arrangement as explained above with thesupply port connectable to a source of a motive fluid and the exhaustport connectable to an dumping space for the motive fluid, at least onepressure transferring unit connected to the at least one outlet/inletopening, transferring pressure from the motive fluid to a fluid to bepressurized.

According to one aspect the pressure transferring unit may be anaccumulator, another possibility is that it may be a gas driven liquidpump, a piston arrangement, a membrane pump system a hose or otherelement which may transfer pressure from one fluid to another fluid.

According to one aspect of the invention there may be one pressuretransferring unit connected to each set of outlet/inlet openings. And inone embedment there may be four sets of inlet/outlet opening, connectedto four pressure transferring units. The pressure transferring unitsthen being in different states as the valve element is rotated relativethe valve housing, and in different states compared with each other.This gives a more even supply of pressurized fluid from the system.There may be more than four inlet/outlet openings sets and pressuretransferring units, or less but the latter might give less even supplyof pressurized fluid, of course dependent on the rotational speed of thevalve element relative the valve housing. In another possible embodimentthere may be two pressure transferring units connected to each set ofinlet/outlet openings, which then forms tow sets of pressuretransferring units which are operated in parallel.

The invention will now be explained with non-limiting embodiments andwith reference to the attached drawings, where

FIG. 1 shows an exploded view of a valve arrangement according to theinvention

FIG. 2 shows a part longitudinal cross section through the valvearrangement

FIG. 3 shows a see through view of the valve arrangement,

FIG. 4 shows four cross sections through the valve arrangement atdifferent axial positions,

FIG. 5 shows a pressurizing system using the valve arrangement.

In FIG. 1 there is shown a valve arrangement having a valve housing 1, avalve element 2 and a ceramic liner 3, where the valve element 2 and theceramic liner 3 should be moved into the housing as shown in FIGS. 2 and3.

The valve element 2 has an outer mainly cylindrical shape with arotation axis 20 for rotation of the valve element 2 relative the valvehousing 1 to operate the valve in different positions. Close to one endof the cylindrical shape there is in the outer surface of the valveelement formed a first circumferential groove 21. Two first bores 22,whereof one is shown in FIG. 1, extend from this circumferential groove21 for a distance mainly parallel to the rotation axis 20 along thevalve element. This first bore 22 is formed as a groove in the outersurface of the valve element. Close to an end of the valve element 2opposite the end with the first circumferential groove 21, there isarranged a second circumferential groove 24. The first bores 22 are notconnected to this second circumferential groove 24. Parallel to thesefirst bore 22 there is arranged two second bores 23, whereof one isshown in FIG. 1. These second bores 23 extends from the secondcircumferential groove 24 and a distance along the valve element 2, inthe direction towards the first circumferential groove 21, but not allthe way. Around a circumference between the circumferential grooves whenseen in a longitudinal direction, there are alternating first and secondbores in the outer surface of the valve element.

When the valve element 2 is positioned within the housing 1 the firstcircumferential groove 21 is aligned with two supply ports 11 arrangedas through going openings in the housing 1. With the circumferentialgroove it would have been enough with only one supply port 11, but twomakes the system even more pressure balanced. The second circumferentialgroove 24 in the valve element is aligned with two exhaust ports 12 inthe housing 1, when the valve element 2 is positioned within the housing1, as can bee seen in FIG. 2. Between the supply ports 11 and theexhaust ports 12 there are in the shown embodiment arranged four sets ofinlet/outlet opening, 13,14,15,16 in the valve housing 1, as can be seenin FIG. 3. These sets of inlet/outlet openings are arranged at differentpositions along the rotations axis of the valve element and also atdifferent angles around the rotation axis, as best shown in FIGS. 1 and4. FIG. 4; 4 a,4 b,4 c,4 d shows four cross section at differentpositions along the rotation axis of the valve element 2, taken atpositions of each set of inlet/outlet openings 13,14,15,16 in thehousing 1, for one position of the valve element 2 relative the valvehousing 1.

As can be seen from the figures when the valve element 2 is in oneposition relative the housing 1 the supply port 11 is connected to oneinlet/outlet set, the second inlet/outlet set 14. This as the valveelement 2 is rotated to a position relative the housing such that thefirst bore 22 which always in connected to the supply port 21, and inthe shown embodiment is formed in the outer surface of the valve elementis aligned with the second inlet/outlet set 14, FIG. 4 b. The secondbore 23 is at the same time aligned with the fourth set of inlet/outletopenings 16, FIG. 4 d. The fourth set of inlet/outlet openings 16 isthereby connected to the exhaust port 12. The first and second set ofinlet/outlets 13, 15 are positioned in the housing such that neither thefirst bore 22 or the second bore 23 are in contact with these sets ofopening, thereby closing these openings, FIG. 4 a, FIG. 4 c.

When the valve element 2 is rotated 90 degrees within the housing inrelation to what is shown in FIG. 4, the first and second bore 22,23will be in contact with the first and third inlet/outlet openings sets13,15, while the second and fourth sets 14,16 are closed. And when thevalve element 2 is rotated even further 90 degrees the first bore 22will be in contact with the fourth set 16 and the second bore 23 will bein contact with the second set 14.

In the shown embodiment there are shown sets of two openings or ports.It is possible to form the valve arrangement with only one opening orport in one set, or it is possible to form it with three, four or eightaround the circumference. By having sets with more than one, there isthe possibility of having the valve arrangement pressure balanced.

In FIG. 5 there is shown one application where the valve arrangement maybe used. The figure shows a system for providing pressure in a liquidwithout the use of a normal pump. There are in the system shown fourpressure transforming units 6 which in this case are four accumulators6. The accumulators 6 are all separately connected to a low pressureliquid line 9 with an inlet check valve 7 in this connection and theyare all also connected to a high pressure liquid line 10 with an outletcheck valve 8 in that connection. The inlet check valve 7 only allowsfluid to flow from the low pressure liquid line 9 and into theaccumulators 6 when there is a given pressure difference between the lowpressure line and the accumulator. When the pressure is higher in theaccumulator, this inlet check valve 7 will be closed. The outlet checkvalve 8 only allows fluid to flow out of the accumulator 6 when thepressure within the accumulator 6 has reached a given higher pressure,compared with the pressure within the high pressure liquid line 10.There are inlet check valves 7 and outlet check valves 8 for each of theaccumulators 6.

The accumulators 6 are also connected to a valve arrangement accordingto the invention for providing a motive gas in the accumulators. Thevalve arrangement are connected to a motive gas supply fluid line 4 anda motive exhaust fluid line 5, and a motor/control arrangement forrotating the valve element relative the housing.

A gas is fed through the gas supply line 4 through a supply port in thevalve housing. The gas is then lead through the circumferential grooveand the first bore, dependent on the relative rotational position of thevalve element within the housing, lead out through one inlet/outlet portin the valve housing and through to one of the accumulators 6. Possiblyat the same time another accumulator 6 is through another inlet/outletport, the second bore, the second circumferential groove and the exhaustport connected to the motive exhaust fluid line 5.

As the valve element is rotated, this inlet/outlet port of one set formsin a first position a connection between the motive supply fluid line 4and the accumulator 6, a second position closes this connection, a thirdposition opens a connection between the motive exhaust fluid line 5 andthe accumulator 6, and in a fourth position closes this connection.Where after it is in a fifth position where the accumulator again isconnected to the motive supply fluid line or this is the first position,both starting the sequence of connecting to motive fluid line, closingthis, connecting to exhaust fluid line, closing that, again as the valveelement is rotated relative the valve housing.

As there are four accumulators and also four inlet/outlet opening sets,an accumulator goes through the steps of being pressurized by addingmotive fluid and then providing pressurized fluid out of the accumulatorand into the high pressure liquid line, being depressurized as it isconnected to the exhaust line and then allowing lower pressure liquidinto the accumulator. The four accumulators 6 and the valve arrangementare arranged such that each accumulator is in another step of thesequence compared to the other accumulators. This gives the situationwhere there are few and minor if any pressure pulses in the highpressure liquid line as there when one accumulator is finishing its stepof providing higher pressure liquid another comes into this step.

The invention has now been explained with reference to non-limitingembodiments. A skilled person will understand that there may be madealternations and modifications to the shown embodiments that are withinthe scope of the invention as defined in the attached claims. Forinstance the valve element may be formed with four first and secondbores and then four inlet/outlets in each set in the valve housing. Thisgives another frequency on the switch between the different positions inthe sequence with the same rotation speed of the valve element relativethe housing. There may be more or fewer than four inlet/outlet openingssets. The first and second bore may be formed as bores within the valveelements instead of as grooves in the outer surface. Then the supplyport and the exhaust port don't need to be on opposite sides of thegroup of inlet/outlet opening sets. There is also the possibility thatan inlet outlet/opening set is connected to two pressure transferringunits which than are operated in parallel.

1. A valve arrangement comprising: a housing; and a mainly cylindricalvalve element arranged rotatable within the housing; the housingcomprising at least one supply port, at least one exhaust port and atleast one set of two outlet/inlet openings, the supply and exhaust portsand the outlet/inlet openings being arranged at a distance from eachother along a rotation axis of the valve element; the valve elementcomprising at least two first bores arranged on opposite sides of thevalve element, the first bores extending along the rotation axis andconnecting the supply port with said at least one set of outlet/inletopenings in a first position of the valve element; the valve elementfurther comprising at least two second bores arranged on opposite sidesof the valve element, the second bores extending along the rotation axisand connecting said at least one set of outlet/inlet openings with theexhaust port in a second position of the valve element; wherein thefirst and second bores are configured such that they are separated fromeach other; and wherein the valve arrangement comprises a firstcircumferential groove connecting the supply port with the first boresand a second circumferential groove connecting the exhaust port with thesecond bores.
 2. The valve arrangement according to claim 1, wherein thehousing comprises at least two sets of two outlet/inlet openings, thetwo sets of outlet/inlet openings and the first and second bores beingconfigured such that the first bores in one position of the valveelement are in contact with one set of the outlet/inlet openings and inanother position of the valve element are in contact with the other setof outlet/inlet openings.
 3. The valve arrangement according to claim 1,wherein the at least one set of outlet/inlet openings is arrangedbetween the supply port and the exhaust port as seen along the rotationaxis of the valve element.
 4. The valve arrangement according to claim1, wherein the first and second bores are formed as grooves in an outersurface of the valve element.
 5. The valve arrangement according toclaim 1, wherein the first and second circumferential grooves are formedin the valve element.
 6. The valve arrangement according to claim 1,wherein the housing comprises at least two sets of two outlet/inletopenings, the first set being connectable to a first unit and the secondset being connectable to a second unit, the outlet/inlet openingsconnectable to the first unit being staggered around the housing inrelation to the outlet/inlet openings connectable to the second unit,thereby leading fluid towards the first unit in a first position of thevalve element and then the second unit in a second position of the valveelement.
 7. The valve arrangement according to claim 1, wherein thehousing comprises one set of two supply ports, one set of two exhaustports and at least one set of two outlet/inlet openings, and wherein thesupply ports, the exhaust ports and the outlet/inlet openings of each ofthese sets are arranged around the circumference of the valve elementgenerally opposite each other.
 8. The valve arrangement according toclaim 1, further comprising a ceramic liner arranged between the valveelement and the valve housing.
 9. A system for pressurizing a fluid withthe use of a motive fluid, comprising: a valve arrangement whichincludes a housing and a generally cylindrical valve element rotatablypositioned in the housing; the housing comprising at least one supplyport, at least one exhaust port and at least one set of two outlet/inletopenings, the supply and exhaust ports and the set of outlet/inletopenings being axially spaced from each other; the valve elementcomprising at least two longitudinal first bores which are located onopposite sides of the valve element and which connect the supply portwith said at least one set of outlet/inlet openings in a first positionof the valve element, and at least two longitudinal second bores whichare located on opposite sides of the valve element and which connectsaid at least one set of outlet/inlet openings with the exhaust port ina second position of the valve element, the first and second bores beingconfigured such that they are separated from each other; the valvearrangement further comprising a first circumferential groove connectingthe supply port with the first bores and a second circumferential grooveconnecting the exhaust port with the second bores; wherein the supplyport is connectable to a source of the motive fluid and the exhaust portis connectable to a dumping space for the motive fluid; and wherein atleast one pressure transferring unit is connected to the at least oneset of outlet/inlet openings for transferring pressure from the motivefluid to the fluid to be pressurized.
 10. The system according to claim9, wherein the pressure transferring unit is an accumulator.
 11. Thesystem according to claim 9, wherein a respective pressure transferringunit is connected to each set of outlet/inlet openings.